I don't want to sound extra handicapped but eh... What do you mean with 'Functional front-ended website'?
Also, I will 'try' to host add-ons with pictures and some explanation.
You need to program your front-end. That basically means the way the page looks, the layout. Work on the HTML, CSS, Javascript, etc. Once you have the page looking fine, and functional, then you should work on the backend (PHP programming)
Also, don't host add-ons, There is already a site for that. You could link to the site's actual specific download, and then the image also. However, if you want to have users upload their addons, you will need some sort of Database setup, (which involves both PHP
and MySQL)